F150 MISFIRE/POWER LOSS

Lifted with 35" tires. Installed 4.10 gears in diffs. Shutters/misfires when idling and lost all power on hills at highway speeds. Kicked a misfire cyl 1 code- I changed the coil pack/wire/plug, still ran rough. Kicked a P0.174 code (lean on bank 1) so I changed MAF sensor, oxy sensors, IAC sensor, PCV-valve and checked for vacuum leaks by spraying flammable parts cleaner on all hoses while @ idle. Now oil temp gauge is up/down, goes into red while motor is cold but running higher RPM's and sticks there, then drops back to normal at idle. Ran can of Seafoam through intake from vacuum on brake booster @ idle to smoke out the carbon buildup in intake, still wants to shutter and give " misfire cyl 1" code. At hard acceleration from idle I can hear what sounds like a valve rattle or maybe the lack of presece of fuel? I have now done the unthinkable and dropped it off at the dealer to get their diagnosis. I was thinking sensors/timing until the oil temp problem. Now I am lost other than a possible bad brainbox. Please help! I know it's high mileage, but all problems can be fixed, right?

No ground straps were cut. I installed a 6" suspension lift, not a body lift. One thing I'm considering is I had my windshield replaced this past march. The company did a terrible job and it leaked pretty bad down the inside of the dash on the drivers side and filled up in the floorboard before they finally came back to fix it. A week or so afterwards I had an airbag light that came on and off but finally cleared up. I guess the water maybe could have damaged the computer. If I were to change the computer, what route should I be looking at?